Abstract The objective of this work was to evaluate the combining ability of S3 forage maize (Zea mays) progenies for traits related to forage yield and bromatological quality, with and without the ear, as well as to evaluate the ability of testers to discriminate progenies for these traits. The trials were carried out in the 2017/2018 and 2018/2019 crop seasons, in the municipality of Guarapuava, in the state of Paraná, Brazil. Topcross hybrids obtained from the crosses of 28 S3 maize progenies with three testers were evaluated. The following forage qualitative traits of the whole plant and of the plant without the ear were evaluated: neutral and acid detergent fibers, lignin, and in situ dry mass digestibility, as well as digestible dry mass yield of the whole plant. The progenies that stood out for forage qualitative traits were 85.1 and 42.1 for the whole plant and for the plant without the ear, respectively. For the qualitative and productive traits of whole-plant forage, progenies 91.1, 106.2, 126.2, 138.1, 152.1, 235.1, and 251.1 are promising to continue in the breeding program aiming to generate hybrids with a high yield and fiber quality. Testers LEM3 and AG8025 are efficient in discriminating progenies for forage yield and bromatological traits.

Resumo O objetivo deste trabalho foi avaliar a capacidade de combinação de progênies S3 de milho (Zea mays) forrageiro em relação a características relacionadas com o rendimento e a qualidade bromatológica da forragem, com e sem a espiga, bem como avaliar a capacidade de testadores para a discriminação das progênies para estas características. Os ensaios foram realizados nas safras de 2017/2018 e 2018/2019, no município de Guarapuava, no estado do Paraná, Brasil. Foram avaliados os híbridos topcross obtidos dos cruzamentos de 28 progênies de milho S3 com três testadores. As seguintes características qualitativas da forragem da planta inteira e da planta sem a espiga foram avaliadas: fibras em detergente neutro e ácido, lignina e digestibilidade in situ da massa seca, além do rendimento da massa seca digerível de toda a planta. As progênies que se destacaram quanto às características qualitativas da forragem foram 85.1 e 42.1 para a planta inteira e para a planta sem a espiga, respectivamente. Para as características qualitativas e produtivas da forragem da planta inteira, as progênies 91.1, 106.2, 126.2, 138.1, 152.1, 235.1 e 251.1 são promissoras para continuar no programa de melhoramento com vistas à geração de híbridos com altos rendimento e qualidade de fibra. Os testadores LEM3 e AG8025 são eficientes na discriminação de progênies para as características produtivas e bromatológicas das forragens.

RESUMO O trabalho teve por objetivo selecionar progênies S3 de milho super doce com base no desempenho agronômico, avaliadas em topcrosses com o testador Honey Sweeter, de base genética estreita. O experimento foi conduzido em Guarapuava-PR. Foram avaliados 22 híbridos topcrosses e três testemunhas, em duas épocas de semeadura, no delineamento em blocos ao acaso, com três repetições. Foram avaliadas seis características: produtividade total de espigas sem palha, produtividade comercial de espigas sem palha, produtividade de grãos, comprimento de grãos, diâmetro de espiga e teor de sólidos solúveis totais. Considerando o conjunto das características avaliadas, os topcrosses com as progênies D2-07, D3-28, D4-53 e D5-24 foram superiores aos demais; portanto, essas progênies devem seguir no processo de endogamia e ser avaliadas em cruzamentos com linhagens elites com potencial para geração de híbridos simples de milho super doce competitivos.

ABSTRACT The aim of this study was to select S3 progenies of super sweet corn based on agronomic performance, evaluated in topcrosses with the narrow genetic base tester Honey Sweeter (Seminis®). The experiment was carried out in Guarapuava-PR. We evaluated 22 topcross hybrids and three checks, in two sowing times, in randomized blocks design with three replications. Six traits were evaluated: total yield of husked ears, commercial yield of husked ears, grain yield, grain length, ear diameter and total soluble solids content. Considering the set of evaluated traits, the topcrosses with progenies D2-07, D3-28, D4-53 and D5-24 were superior to the others; therefore, these progenies should continue in the inbreeding process and be evaluated in crosses with elite inbred lines with potential to generate competitive super sweet corn single hybrids.

RESUMO O milho super doce é classificado como um tipo especial de milho, por possuir genes que promovem o acúmulo de açúcar nos grãos, diminuindo significativamente o teor de amido no endosperma. Este trabalho teve como objetivo avaliar o desempenho agronômico de híbridos experimentais de milho super doce, portadores do gene shrunken-2 (sh2), para a identificação e seleção de híbridos promissores para a região sul do Brasil. O experimento foi realizado em duas épocas de semeadura na safra 2017/18, no campo experimental da UNICENTRO, em Guarapuava-PR, Brasil. Foram avaliados 32 híbridos experimentais resultantes de um dialelo parcial 8x4 entre linhagens de milho super doce, provenientes de quatro populações distintas, juntamente com dois híbridos comerciais (BRS Vivi e Tropical Plus) utilizados como testemunhas. Foram avaliados caracteres de interesse agronômico e comercial: florescimento masculino (FM), índice de empalhamento da espiga (IE), rendimento de espigas despalhadas (RED), rendimento de grãos (RG), prolificidade comercial (PC), porcentagem de espigas comerciais (PEC), coloração (COR) e teor de sólidos solúveis (SS) dos grãos. Houve diferenças significativas entre os híbridos experimentais, exceto para COR. Não houve efeito significativo da época de semeadura para SS e a interação genótipos x épocas foi significativa para os caracteres RED, RG, PC, PEC e COR. Há híbridos experimentais promissores, competitivos com híbridos comerciais utilizados no Brasil para a produção de milho super doce. Os híbridos experimentais D2-61 x D5-41 e D3-10 x D5-43 foram superiores ao demais genótipos experimentais. O híbrido experimental D2-61 x D5-41 tem potencial de atendimento às exigências do mercado atual de milho super doce.

ABSTRACT Super sweet is classified as a special type of corn, due to the presence of genes which promote sugar accumulation in grains, significantly reducing starch content in the endosperm. This study aimed to evaluate the agronomic performance of experimental super sweet corn hybrids, carrying the gene shrunken-2, in order to identify and select promising genotypes for Southern Brazil. The experiments were carried out in two sowing seasons in 2017/18, in the experimental field of UNICENTRO, Guarapuava-PR, Brazil. Thirty-two experimental hybrids resulting from an 8x4 partial diallel among super sweet corn inbred lines from four distinct populations were evaluated along with two commercial hybrids (BRS Vivi and Tropical Plus) used as checks. Traits of agronomic and commercial interest were evaluated: male flowering (MF), husk covering index (HCI), yield of husked ears (YHE), grain yield (GY), commercial prolificacy (CPR), percentage of commercial ears (PCE), color (COL) and soluble solids (SS) of the grains. We verified significant differences among the experimental hybrids, except for COL. There was no significant effect of sowing season regarding to SS. Genotypes x seasons interaction was significant for YHE, GY, CPR, PCE and COL. There are promising experimental hybrids showing performances superior to commercial super sweet corn hybrids used in Brazil. The experimental hybrids D2-61 x D5-41 and D3-10 x D5-43 were superior to the other experimental genotypes. The experimental hybrid D2-61 x D5-41 shows potential to meet the demands of the current super sweet corn market.

ABSTRACT. Maize forage is commonly used as silage in milk and beef cattle livestock production systems. Despite the wide variety of maize hybrids with high potential for grain production, few available hybrids have been developed exclusively for forage aptitude. The present study aimed to select S3 maize progenies derived from the single hybrid AS1572 based on the combining ability of forage traits in topcrosses with testers AG8025, 70.H26.1, and MLP102. The 135 resulting topcross hybrids were assessed in partial diallel in Guarapuava and Rio Bonito do Iguaçu, Paraná State, Brazil. Were evaluated the contents of neutral detergent fiber (NDF, %DM) and acid detergent fiber (ADF, %DM), forage dry matter yield (DMY, t ha-1), and in situ digestibility of forage dry matter (DIG, %DM). For all evaluated traits, the variability allowed us to select superior progenies. Progenies 3.1, 22.1, and 39.1stood out in terms of NDF, ADF, and DIG, whereas progenies 47.1, 73.1, 79.1, and 90.2 were efficient in increasing the forage dry matter yield. The testers AG8025 and 70.H26.1, of narrow genetic base, are the best to explore genetic variability among progenies.

ABSTRACT Super sweet corn breeding must develop hybrids that fully meet the expectations of the market. In this sense, the determination of keytraits for the selection of sweetcorn genotypes is a fundamental condition for breeding success. The objective of this work was to identify key traits for the selection of promising and contrasting genotypes of super sweet corn. The experiments were carried out in Guarapuava (PR), in two sowing dates. Seventeen traits related to the yield and quality of the ear were evaluated. To perform the multivariate analysis, data were subjected to diagnosis of multicolinearity, analysis of canonical variables, genetic divergence, hierarchical clusters, factor analysis, and canonical correspondence analysis. Grain yield, yield of dehusked ears, and number of commercial ears were considered related key traits in the identification of promising super sweet corn genotypes. Hybrid D3-20 × D5-41 presented higher averages than the others, considering the yield related keytraits.

Resumo: O objetivo deste trabalho foi identificar genótipos de milho (Zea mays) com potencial forrageiro e avaliar a eficiência dos testadores em discriminar características forrageiras em cruzamentos topcrosses, ao se considerar a contribuição de genes aditivos e não aditivos. O experimento foi conduzido nas safras de 2015/2016 e 2016/2017, no delineamento de blocos ao acaso, com três repetições. Avaliaram-se 30 progênies S3 de milho em cruzamentos topcrosses com os testadores AG8025, P30B39, MLP102, 60.H23.1 e 70.H26.1. Foram avaliadas as seguintes características: produtividade de massa seca da forragem, fibra em detergente neutro, fibra em detergente ácido e degradabilidade da massa seca da forragem. As progênies 205.2, 159.6 e 199.2, nessa ordem, apresentaram o melhor desempenho para potencial forrageiro. Os testadores 60.H23.1 e 70.H26.1 melhor expressaram a variabilidade genética existente entre as progênies. Para todas as características nas duas safras, há o predomínio da ação de genes de efeitos não aditivos.

Abstract: The objective of this work was to identify corn (Zea mays) genotypes with forage potential and to evaluate the efficiency of testers to discriminate forage traits in topcrosses, considering the contribution of additive and nonadditive genes. The experiment was carried out in the 2015/2016 and 2016/2017 crop seasons, in a randomized complete block design with three replicates. Thirty S3 corn progenies were evaluated in topcrosses with the AG8025, P30B39, MLP102, 60.H23.1, and 70.H26.1 testers. The following traits were assessed: forage dry mass yield, neutral detergent fiber, acid detergent fiber, and forage dry mass degradability. Progenies 205.2, 159.6, and 199.2, in this order, presented the best performance for forage potential. Testers 60.H23.1 and 70.H26.1 better expressed the genetic variability between progenies. For all traits in both crop seasons, there is a predominance of the action of genes of nonadditive effects.